Calcium carbonate is widely used as a filler or a pigment of plastics, coating materials, ink, sealants, adhesives, plastisols, paper, rubber, etc. Particularly, calcium carbonate is an important material as a filler of synthetic resins.
In resin compositions blended with calcium carbonate, there are curable type resin compositions for sealants, adhesives, coating materials, waterproofing agents, floors, plastisols, etc. For example, with respect to the sealants, the sealant is widely used in the fields of constructions, automobiles, floors, etc., for the purpose of waterproofing and sealing. When it is used in these fields, it is often applied to a vertical area, and therefore it needs not to run during a period of time from its application to curing as a matter of course and needs to have high viscosity and high thixotropy to a proper extent. But, when it has high viscosity and thixotropy, adhesion between a member to be applied and the resin composition is often reduced and this generally leads to deteriorate slip resistance, and therefore a sealing material having both of excellent slump resistance and slip resistance is desired.
And, for example, particularly in plastisols for automobile bodies, thermoplastic polymer particles are generally used, and spray coating is usually common and it becomes important to prevent sags and slip of sols after spraying.
As the thermoplastic polymer particles, there have been frequently used polyvinyl chlorides represented by copolymers of vinyl chloride polymer or vinyl chloride with vinyl acetate because it has superior anticorrosion characteristics, and can fill a crevice in a joint portion well and form a relatively thick film, but in recent years, the stream of post-vinyl chloride is accelerated from environmental issues, and as an alternative thereto, an acrylic sol, a urethane sol, a modified silicone sol, etc. have been developed. Particularly, an acrylic plastisol, which is formed by dispersing acrylic polymer particles together with a filler in a plasticizer has been developed and commercialized. Since the acrylic plastisol has forms, workability and processability equivalent to a polyvinyl chloride composition, it has been studied to be used as an alternative to the polyvinyl chloride composition and a coating, having strength and durability compatible to a polyvinyl chloride plastisol, has become available.
However, since the acrylic polymer particles used in the acrylic plastisol has a weak intermolecular force acting on between molecules in comparison to vinyl chloride polymer particles, a plasticizer is apt to be captured in between molecules, and since the captured plasticizer bleeds with time, the acrylic plastisol has a problem of tending to slip due to this bled plasticizer in forming a film by heat.
On the other hand, in Japanese Unexamined Patent Publication No. 2002-235015, the surface coated calcium carbonate, which is coated with a mixture of a saturated fatty acid (salt) and an unsaturated fatty acid (salt) and further coated with an organic compound such as a phthalic acid ester, etc., is proposed in an attempt to provide calcium carbonate capable of imparting dispersibility, adhesion and viscosity stability.
Also, in Japanese Unexamined Patent Publication No. 11-60950, there is proposed calcium carbonate surface treated with at least one kind selected from sulfate ester type anion surfactants and sulfonic acid type anion surfactants, and a fatty acid (salt) in order to attain a curable composition, which has a long pot life and proper viscosity and is good in workability.
Further, in Japanese Unexamined Patent Publication No. 2002-220547, there is proposed the surface treated chain calcium carbonate surface treated with organic treating agents such as a fatty acid, a resin acid and a surfactant to provide a coat with slip resistance, adaptability to joints and high strength.
However, the above-mentioned products cannot be necessarily said to be satisfactory in point of the effectiveness of improving slip resistance.
Thus, fillers and resin compositions which can resolve the above problems are desired.
Considering such a situation, the present invention provides surface treated calcium carbonate, which can develop particularly excellent slip resistance when it is mixed, for example, in sealing materials represented by a modified silicone or plastisols represented by a polyvinyl chloride plastisol and a acrylic plastisol, and provides a resin composition containing the surface treated calcium carbonate.
The present inventors conducted studies earnestly in order to resolve the above-mentioned problems and consequently have known that a ratio of the fatty acid surface treatment agent having specific carbon atoms, which constitutes a surface treatment agent, has a large effect on the slip resistance and found out that it is possible to resolve the above problems by using calcium carbonate surface treated with a surface treatment agent containing a fatty acid having specific carbon atoms, and have completed the present invention.